President Carter's family peanut warehouse regularly and substantially overdrew its account with the National Bank of Georgia and apparently received preferential treatment on multimillion-dollar loans, according to a report released yesterday by the NBG.

The overdraft problem became so severe that, in June 1977, the bank's loan officer wrote Billy Carter, the president's brother, to say the bank was "holding approximately $400,000" in payments requests "with no funds to cover" them, the report said.

The report also said, without elaboration, that interest rates on loans to the Carter operation were scaled down regularly, sometimes at Bert Lance's direction and another time for an "undocumented" reason.

The report, ordered as part of a settlement of a government suit, covers the bank's activities from the time Lance became its president in January 1975 up to the present. Lance became Carter's budget director in January 1977 and resigned under pressure in October 1977 because of his past financial affairs.

The White House issued no response to the report.

As president of NBG, Lance had arranged a line of credit for the Carter family warehouse. The line reached a peak of $3.7 million on Nov. 2, 1976. The report said the loans to the business were "the first loans of this type handled by NBG, and they appear to have been poorly managed by the bank."

For the most part, the 131-page report affirms earlier findings by two federal agencies, the Securities and Exchange Commission and the comptroller of the currency, but the details of NBG's loans to Carter's business were not disclosed previously.

The SEC and the comptroller filed suit last April against Lance, the NBG and the Calhoun (Ga.) First National Bank, charging them with fraud and deceit. The NBG report issued yesterday, prepared by a special committee of the bank's board of directors, was part of the settlement. The Calhoun bank agreed to issue a similar report.

Carter placed the warehouse operation in a blind trust when he became president in January 1977.

There has been speculation that some of the NBG loans may have been diverted to Carter's presidential campaign, but the bank report denies this.

"We have seen no evidence that the proceeds of these loans were, at least to the knowledge of anyone at NBG, used outside the Carter peanut business," the report said.

The first loan, $600,000 to build a peanut sheller, was extended on June 12, 1975, some five months after Lance joined NBG as president.

On Dec. 18, 1975, NBG loaned another $300,000 to the Carters for construction of a new warehouse.

The interest rate on the two loans was regularly scaled down, sometimes at Lance's direction. For example, the report says: "At the loan administration committee meeting on Jan. 22, 1976, the account officer reported a reduction in the rate to prime plus 2 1/2 percent. This rate change was directed by Lance."

Prime is the lending rate banks charge their best business customers.

While not saying whether the loans were promptly repaid, the bank report does say that they were regularly refinanced and new terms for repayment set down.

By June 1977 they were being repaid at $80,000 annually, and the interest rate had dropped to one-half per cent over prime.

NBG, at Lance's direction, also granted a $3 million line of credit to the Carter peanut business in July 1975, increasing it to $9 million that September. Only $3.7 million of the credit line was drawn down, the report says.

The report notes that NBG officers worried that "borrowings under the line of credit might exceed NBG's legal lending limit."

NBG's lawyer said the limit on the Carter loans was $5.5 million, and apparently the total Carter loans never exceeded that amount.

The report says that the bank ignored problems of insufficient funds on the Carter account. "This practice apparently resulted in part from pressure by Lance to avoid overdrafts, the report said.

Gerald Rafshoon, a presidential assistant, also had extensive borrowings from NBG for himself and his advertising agency. That agency also handled advertising for the Carter presidential campaign.

"We have not found evidence of impropriety on the part of NBG with respect to any of these loans," the report said.

The report says that Lance and others, including President Carter, used NBG's plane for nonbank purposes. Noting that the bank already has collected $808.65 from the Committee to Lance should reimburse the bank for this, the report says.

The report says hundreds of thousands of dollars in bad loans to Lance's family and associates were shifted by Lance from the Calhoun bank to NBG after the loans were challenged by bank examiners. Similar allegations were made in the government's suit.

Elect Jimmy Carter for its use of the plane, it recommends that NBG seek another $629.85 from President Carter.

The report says that the Internal Revenue Service disallowed $19,200 charged to the bank by Lance for liquor, wine, limousine service and airplane expenses because of improper documentation.

It says, "Lance carefully avoided taking responsibility for any of these loans."

The report adds, "It also appears that some of the loans were made with Lance at least knowing that the only source of repayment would be a loan from another bank or a complete liquidation of the borrowers' assets."